The incidence of non-Hodgkin's lymphoma (NHL) is steadily increasing worldwide. At present, it is the sixth most commonly diagnosed cancer in France, with 10 000 estimated new cases and 5200 deaths annually. An increasing NHL incidence at a rate of 3-4% per year was observed for the 1970s and 1980s. This stabilized in the 1990s, nevertheless still with an annual rise of 1-2%, resulting in almost a doubling of the NHL incidence during last 40 years. This rise has been noted worldwide, particularly in elderly persons >55 years. Increases in high-grade NHL and extranodal disease are predominant. There is about 80% of B-cell histology, approximately 90% of follicular lymphomas and about 70% of aggressive lymphoma patients present with disseminated disease at diagnosis. The prognosis of NHL depends on the histological type, stage and treatment. Indolent lymphomas have a relatively good prognosis with survival time as long as 10 years, but they are usually incurable in advanced stages. Aggressive NHL constitutes about 50% of all cases of NHL in Western Europe. Approximately 50 - 60% of these patients can be cured with immuno-chemotherapy regiments. Subsequently, almost 50% of patients will eventually relapse or become refractory to treatment. The prognosis for patients with refractory or relapsed aggressive NHL is generally poor. The response rates to salvage therapy regimens range from 20 to 40%. Patients who present with refractory disease have the worst prognosis, with a median survival of less than six months. Only a minority of patients can be given high dose chemotherapy, the majority being ineligible due to disease progression.